The objective of this project is to study the epidemiology of elevated blood pressure and hypertension during adolescence. The study subjects will be drawn from a population for which extensive longitudinal data, collected prospectively, are available. Three samples of adolescents will be studied: (1) a random sample stratified by age, sex, and race; (2) a sample of adolescents whose mothers had toxemia of pregnancy; and (3) a sample of adolescents who had elevated blood pressure during childhood (i.e., at age seven). Antecedent variables include maternal and prenatal factors, complete postnatal medical histories, physical growth data, psychological test data, and detailed information about socioeconomic status. Current assessments will take place at three annual intervals and will include demographic information, recent medical history, blood pressure records, growth and maturation measures (height, weight, skinfold thicknesses, hand-wrist radiographs, measures of steroid hormones), and psychological profiles. Our analyses will aim to clarify the relationship between elevations in blood pressure, antecedent variables, and current parameters of physical growth, body composition, mental health status, socioeconomic status, and sexual maturation.